In a heat pump type air-conditioning apparatus, during a heating operation, frost may occur on an outdoor heat exchanger which serves as an evaporator. Heat exchange is inhibited by the frost. Thus, when frost is detected, a defrost operation is performed for removing the frost. When the defrost operation is performed, the frost formed on the outdoor heat exchanger is melted, dropped as drain water onto a base of an outdoor unit, and then discharged through a drain discharge hole to the outside. In some cases, in a cold climate area, frost easily occurs, and drain water dropped on a bottom plate of an outdoor unit refreezes at a low outside air temperature before discharged from the drain discharge hole. Thus, there are some outdoor units in which a heater for removing frozen drain water is provided at a bottom plate.
There is a method of fixing the heater to the bottom plate of the outdoor unit by fastening the heater thereto using a heater fixture through bolts (e.g., see Patent Literature 1). Specifically, in Patent Literature 1, a heater fixture has, at one end side thereof, a recess surrounding an outer peripheral surface of the heater from above, and has, at the other end side, a flat surface fixed to the bottom plate. The flat surface of the heater fixture is fixed to the bottom plate using fastening members such as bolts, whereby the heater is fixed to the bottom plate.